Alert archive / Missouri / Flash Flood Warnings in 2020

Flash Flood Warning 25, NWS St. Louis, MO

June 22, 2020Saint Charles County, Warren County, Missouri

NWS St. Louis, MO issued this flash flood warning at Jun 22, 2020, 5:18 PM CDT for Saint Charles County, Warren County, Missouri. It was in force for 4 hr. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jun 22, 2020, 5:18 PM CDT (22:18 UTC)
Expired
Jun 22, 2020, 9:15 PM CDT
In force
4 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Saint Charles County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 25 km from the middle of the area, began a volume at 22:20 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Jun 22, 5:30 PM CDTFLASH FLOOD2 Ssw Lake Saint Louis, MOA COUPLE OF INCHES OF WATER OVER WEST BOUND LANE OF HIGHWAY N ABOUT A MILE WEST OF INTERSECTION WITH I-64.
Jun 22, 6:00 PM CDTHEAVY RAIN 3.42 W Lake Saint Louis, MORAINFALL IN THE PAST 4 HOURS.
Jun 22, 7:00 PM CDTFLASH FLOODFlint Hill, MOWATER ACROSS MEXICO ROAD ABOUT HALF A MILE SOUTH OF INTERSECTION WITH HIGHWAY P. DEPTH WAS UNKNOWN. WATER RECEDED BY 730 PM.
Jun 22, 7:15 PM CDTHEAVY RAIN 3.321 Sw Flint Hill, MOAN ADDITIONAL 1.09 INCHES IN THE PAST HALF HOUR, SO FAR 3.32 INCHES TODAY.
Jun 22, 7:45 PM CDTHEAVY RAIN 4.63Flint Hill, MOFOR THE DAY SO FAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.3 hours before the alert went out and 246 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2020-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 401 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2020-06-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
401 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
1137 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

188 
WGUS53 KLSX 222218
FFWLSX
MOC183-219-230215-
/O.NEW.KLSX.FF.W.0025.200622T2218Z-200623T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
518 PM CDT Mon Jun 22 2020

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Northwestern St. Charles County in east central Missouri...
  East central Warren County in east central Missouri...

* Until 915 PM CDT.

* At 518 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to three inches of rain have
  already fallen. Flash flooding is ongoing or expected to begin
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, urban areas, 
           highways, streets and underpasses as well as other 
           drainage and low lying areas.

* Some locations that will experience flooding include...
  O'Fallon, Wentzville, Lake St. Louis, Dardenne Prairie, Wright
  City, St. Paul, Innsbrook, New Melle, Josephville, Flint Hill and
  Foristell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 3886 9107 3887 9098 3887 9096 3888 9096
      3889 9087 3887 9082 3888 9081 3890 9081
      3891 9074 3865 9074 3866 9108

FLASH FLOOD...RADAR INDICATED

$$

Byrd
1 follow-up statement
493 
WGUS73 KLSX 230221
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
921 PM CDT Mon Jun 22 2020

MOC183-219-230231-
/O.EXP.KLSX.FF.W.0025.000000T0000Z-200623T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Charles MO-Warren MO-
921 PM CDT Mon Jun 22 2020

...THE FLASH FLOOD WARNING FOR NORTHWESTERN ST. CHARLES AND EAST
CENTRAL WARREN COUNTIES HAS EXPIRED...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3886 9107 3887 9098 3887 9096 3888 9096
      3889 9087 3887 9082 3888 9081 3890 9081
      3891 9074 3865 9074 3866 9108

$$

Byrd

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 22, 2:04 PM CDTSevere Thunderstorm WarningLSXPike26 min
Jun 22, 6:51 PM CDTSevere Thunderstorm WarningLSXLincoln, Saint Charles, Warren39 min

Nearby

Flash Flood Warnings in Missouri, 2020Every flash flood warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.